diff options
Diffstat (limited to 'doc/README.autoboot')
| -rw-r--r-- | doc/README.autoboot | 121 |
1 files changed, 60 insertions, 61 deletions
diff --git a/doc/README.autoboot b/doc/README.autoboot index 20736ca..a6d5f99 100644 --- a/doc/README.autoboot +++ b/doc/README.autoboot @@ -69,25 +69,25 @@ What they do bootretry environment variable - These options determine what happens after autoboot is - stopped and U-Boot is waiting for commands. - - CONFIG_BOOT_RETRY_TIME must be defined to enable the boot - retry feature. If the environment variable 'bootretry' is - found then its value is used, otherwise the retry timeout is - CONFIG_BOOT_RETRY_TIME. CONFIG_BOOT_RETRY_MIN is optional and - defaults to CONFIG_BOOT_RETRY_TIME. All times are in seconds. - - If the retry timeout is negative, the U-Boot command prompt - never times out. Otherwise it is forced to be at least - CONFIG_BOOT_RETRY_MIN seconds. If no valid U-Boot command is - entered before the specified time the boot delay sequence is - restarted. Each command that U-Boot executes restarts the - timeout. - - If CONFIG_BOOT_RETRY_TIME < 0 the feature is there, but - doesn't do anything unless the environment variable - 'bootretry' is >= 0. + These options determine what happens after autoboot is + stopped and U-Boot is waiting for commands. + + CONFIG_BOOT_RETRY_TIME must be defined to enable the boot + retry feature. If the environment variable 'bootretry' is + found then its value is used, otherwise the retry timeout is + CONFIG_BOOT_RETRY_TIME. CONFIG_BOOT_RETRY_MIN is optional and + defaults to CONFIG_BOOT_RETRY_TIME. All times are in seconds. + + If the retry timeout is negative, the U-Boot command prompt + never times out. Otherwise it is forced to be at least + CONFIG_BOOT_RETRY_MIN seconds. If no valid U-Boot command is + entered before the specified time the boot delay sequence is + restarted. Each command that U-Boot executes restarts the + timeout. + + If CONFIG_BOOT_RETRY_TIME < 0 the feature is there, but + doesn't do anything unless the environment variable + 'bootretry' is >= 0. CONFIG_AUTOBOOT_KEYED CONFIG_AUTOBOOT_PROMPT @@ -101,9 +101,9 @@ What they do bootdelaykey2 environment variable bootstopkey2 environment variable - These options give more control over stopping autoboot. When - they are used a specific character or string is required to - stop or delay autoboot. + These options give more control over stopping autoboot. When + they are used a specific character or string is required to + stop or delay autoboot. Define CONFIG_AUTOBOOT_KEYED (no value required) to enable this group of options. CONFIG_AUTOBOOT_DELAY_STR, @@ -111,48 +111,47 @@ What they do specified by the corresponding environment variable), otherwise there is no way to stop autoboot. - CONFIG_AUTOBOOT_PROMPT is displayed before the boot delay - selected by CONFIG_BOOTDELAY starts. If it is not defined - there is no output indicating that autoboot is in progress. - If "%d" is included, it is replaced by the number of seconds - remaining before autoboot will start, but it does not count - down the seconds. "autoboot in %d seconds\n" is a reasonable - prompt. - - If CONFIG_AUTOBOOT_DELAY_STR or bootdelaykey is specified and - this string is received from console input before autoboot - starts booting, U-Boot gives a command prompt. The U-Boot - prompt will time out if CONFIG_BOOT_RETRY_TIME is used, - otherwise it never times out. - - If CONFIG_AUTOBOOT_STOP_STR or bootstopkey is specified and - this string is received from console input before autoboot - starts booting, U-Boot gives a command prompt. The U-Boot - prompt never times out, even if CONFIG_BOOT_RETRY_TIME is - used. - - The string recognition is not very sophisticated. If a - partial match is detected, the first non-matching character - is checked to see if starts a new match. There is no check - for a shorter partial match, so it's best if the first - character of a key string does not appear in the rest of the - string. - - Using the CONFIG_AUTOBOOT_DELAY_STR2 / bootdelaykey2 and/or - CONFIG_AUTOBOOT_STOP_STR2 / bootstopkey #defines and/or - environment variables you can specify a second, alternate - string (which allows you to haw two "password" strings). + CONFIG_AUTOBOOT_PROMPT is displayed before the boot delay + selected by CONFIG_BOOTDELAY starts. If it is not defined + there is no output indicating that autoboot is in progress. + If "%d" is included, it is replaced by the number of seconds + remaining before autoboot will start, but it does not count + down the seconds. "autoboot in %d seconds\n" is a reasonable + prompt. + + If CONFIG_AUTOBOOT_DELAY_STR or bootdelaykey is specified and + this string is received from console input before autoboot + starts booting, U-Boot gives a command prompt. The U-Boot + prompt will time out if CONFIG_BOOT_RETRY_TIME is used, + otherwise it never times out. + + If CONFIG_AUTOBOOT_STOP_STR or bootstopkey is specified and + this string is received from console input before autoboot + starts booting, U-Boot gives a command prompt. The U-Boot + prompt never times out, even if CONFIG_BOOT_RETRY_TIME is + used. + + The string recognition is not very sophisticated. If a + partial match is detected, the first non-matching character + is checked to see if starts a new match. There is no check + for a shorter partial match, so it's best if the first + character of a key string does not appear in the rest of the + string. + + Using the CONFIG_AUTOBOOT_DELAY_STR2 / bootdelaykey2 and/or + CONFIG_AUTOBOOT_STOP_STR2 / bootstopkey #defines and/or + environment variables you can specify a second, alternate + string (which allows you to haw two "password" strings). CONFIG_ZERO_BOOTDELAY_CHECK - If this option is defined, you can stop the autoboot process - by hitting a key even in that case when "bootdelay" has been - set to 0. You can set "bootdelay" to a negative value to - prevent the check for console input. + If this option is defined, you can stop the autoboot process + by hitting a key even in that case when "bootdelay" has been + set to 0. You can set "bootdelay" to a negative value to + prevent the check for console input. CONFIG_RESET_TO_RETRY - (Only effective when CONFIG_BOOT_RETRY_TIME is also set) - After the countdown timed out, the board will be reset to restart - again. - + (Only effective when CONFIG_BOOT_RETRY_TIME is also set) + After the countdown timed out, the board will be reset to restart + again. |